Dielectric material

ABSTRACT

A dielectric material containing at least one of Ca and Sr, Ti, Al, at least one of Nb and Ta, and O, wherein these elements fulfill the following four requirements when represented by a compositional formula, aM l O-bTiO 2 -(½)cAl 2 O 3 -(½)dM 2   2 O 5  wherein M 1  represents the at least one of Ca and Sr; M 2  represents the at least one of Nb and Ta; and a, b, c and d represent each a molar ratio, provided that a+b+c+d=1: 0.436&lt;a≦0.500; 0.124&lt;b≦0.325; 0.054&lt;c≦0.150; and 0.170&lt;d&lt;0.346.

FIELD OP THE INVENTION

This invention relates to a dielectric material and an electroniccomponent using the same. More specifically, it relates to a dielectricmaterial having a relatively high dielectric constant (ε_(x)), a largeunloaded quality factor (Qu) and a small absolute value of temperaturefactor (τ_(f)) of resonance frequency and an electronic component usingthe same.

BACKGROUND OF THE INVENTION

With the rapid advancement of various communication systems with the useof electromagnetic waves in the microwave area including mobilecommunication such as cellular phones and satellite broadcasting, agreat number of dielectric materials have been developed. In thesedielectric materials, priorities are given on three dielectriccharacteristics, namely, dielectric constant (ε_(r)), unloaded qualityfactor (Qu) and temperature factor (τ_(f)) of resonance frequency. Ingeneral, such a dielectric material should have a high ε_(r), a large Quand a small absolute value of τ_(f). However, it is highly difficult tomeet all of these requirements at the same time, since they areincompatible with each other. Therefore, it is desired to control eachof these characteristics within a range according to need.

Known dielectric materials to be employed for the above purposes includeBaO—ZnO'Ta₂O₅ based materials (BaZnTa-based materials) having ε_(r) ofabout 20 to 30 which are disclosed in the following JP-B-59-48484, andBaO—RE₂O₃—TiO₂ (RE: rare earth element) based materials (BaRETi-basedmaterials) having ε_(r) of about 60 to 80 which are disclosed in thefollowing JP-B-59-37526. These materials have been employed in practiceas materials for high-frequency resonators and filters. However, fewmaterials can still exert intermediate ε_(r) values and thus it has beenrequired in recent years to develop materials having intermediate ε_(r)values and being available for high-frequency purposes.

As such materials, CaO—TiO₂—Al₂O₃—Nb₂O₅ based materials (CaTiAlNb-basedmaterials) disclosed in JP-A-2001-302331 and JP-A-2001-302333, andJP-A-2002-308670 filed by the present inventors are known.

SUMMARY OF THE INVENTION

However, the materials according to JP-A-2001-302331 andJP-A-2001-302333 show large scattering in τ_(f), which makes itdifficult to achieve well-balanced dielectric characteristics in detail.Although the material according to JP-A-2002-308670 has excellentproperties and shows controlled scattering in τ_(f) and a relativelylarge Qu, it suffers from a problem of having a relatively low ε_(r).

The invention, which has been completed under the circumstances asdescribed above, aims at providing a dielectric material that can exertan ε_(r) within the intermediate region and a sufficiently controlledτ_(f) while sustaining well-balanced ε_(r) and Qu and an electroniccomponent using the same.

The invention is as follows.

(1) A dielectric material containing at least one of Ca and Sr, Ti, Al,at least one of Mb and Ta and O,

wherein these elements fulfill the following requirements whenrepresented by a compositional formula [aM¹O-bTiO₂-(½)cAl₂O₃-(½)dM² ₂O₅](wherein M^(l) represents Ca and/or Sr; M² represents Nb and/or Ta; anda, b, c and d represent each a molar ratio, provided that a+b+c+d=1):0.436<a≦0.500;0.124<b≦0.325;0.054<c≦0.150; and0.170<d<0.346.

(2) The dielectric material as described in the above (1) wherein a, b,c and d fulfill the following requirements:0.436<a≦0.500;0.124<b≦0.300;0.062<c≦0.150; and0.170<d<0.346.

(3) The dielectric material as described in the above (1) wherein a, b,c and d fulfill the following requirements:0.436<a≦0.500;0.124<b≦0.275;0.069<c≦0.150; and0.170<d<0.346.

(4) The dielectric material as described in the above (1) wherein a, b,c and d fulfill the following requirements:0.444<a≦0.500;0.133<b≦0.275;0.075<c≦0.150; and0.170<d≦0.323.

(5) The dielectric material as described in the above (1) wherein a, b,c and d fulfill the following requirements:0.451<a≦0.500;0.141<b≦0.275;0.079<c≦0.150; and0.170<d≦0.300.

(6) A dielectric material as described in any of the above (1) to (5)which contains 0.01 to 5% by mol of Mn in terms of MnO₂ by referring thetotal molar content of the metal elements, in terms of oxides, containedin the dielectric material as to 100% by mol.

(7) A dielectricmaterial as described in any of the above (1) to (5)which contains 0.01 to 2% by mol of Mn in terms of MnO₂ by referring thetotal molar content of the metal elements, in terms of oxides, containedin the dielectric material as to 100% by mol.

(8) A dielectric material as described in any of the above (1) to (5)which contains 0.01 to 1% by mol of Mn in terms of MnO₂ by referring thetotal molar content of the metal elements, in terms of oxides, containedin the dielectric material as to 100% by mol.

(9) A dielectric material as described in any of the above (1) to (5)which contains 0.01 to 0.6% by mol of Mn in terms of MnO₂ by referringthe total molar content of the metal elements, in terms of oxides,contained in the dielectric material as to 100% by mol.

(10) A dielectric material as described in any of the above (1) to (9)which contains 0.1 to 10% by mol of a rare earth element RE in terms ofRE₂O₃ by referring the total molar content of the metal elements, interms of oxides, contained in the dielectric material as to 100% by mol.

(11) A dielectric material as described in any of the above (1) to (9)which contains 0.1 to 8% by mol of a rare earth element RE in terms ofRE₂O₃ by referring the total molar content of the metal elements, interms of oxides, contained in the dielectric material as to 100% by mol.

(12) A dielectric material as described in any of the above (1) to (9)which contains 0.1 to 6% by mol of a rare earth element RE in terms ofRE₂O₃ by referring the total molar content of the metal elements, interms of oxides, contained in the dielectric material as to 100% by mol.

(13) A dielectric material as described in any of the above (10) to (12)wherein the rare earth element is at least one member selected fromamong La, Nd, Sm, Y and Yb.

(14) A dielectric material as described in any of the above (1) to (13)wherein less than 30% by mol of Ti is substituted by Zr and/or Sn byreferring the total Ti content in the dielectric material as to 100% bymol.

(15) A dielectric material as described in any of the above (1) to (14)wherein less than 30% by mol of Al is substituted by at least one memberselected from among Ga, Y and Yb by referring the total Al content inthe dielectric material as to 100% by mol.

(16) A dielectric material as described in any of the above (1) to (15)wherein less than 30% by mol of M² is substituted by Sb by referring thetotal M² content in the dielectric material as to 100% by mol.

(17) An electronic component having a dielectric member made of adielectric material as described in any of the above (1) to (16).

The dielectric material according to the invention can exert an ε_(r) ofabout 45 to 65 and a sufficiently controlled absolute value of τ_(f)while sustaining well-balanced ε_(r) and Qu. Thus, it is possible toachieve well-balanced dielectric characteristics in detail andappropriate dielectric characteristics can be selected depending onvarious purposes. In particular, the ε_(r) can be highly selectivelydetermined and, furthermore, a small absolute value of τ_(f) can beobtained while sustaining well-balanced ε_(r) and Qu.

In the case where the Mn content is 5% by mol or less in terms of MnO₂,oxygen can be supplied during sintering almost regardless of thedielectric characteristics and thus aimed dielectric characteristics canbe stably obtained.

In the case where the RE content is 10% by mol or less in terms ofRE₂O₃, each of the dielectric characteristics can be controlled at ahigher degree of freedom.

In the case where the RE is at least one member selected from among La,Nd, Sm Y and Yb, Qu and τ_(f) can be particularly improved whilesustaining ε_(r).

In the case where less than 30% by mol of Ti is substituted by Zr and/orSn, each of the dielectric characteristics can be controlled within theneighborhood of the corresponding level of the unsubstituted compositionso that desired combinations of dielectric characteristics can beobtained in greater detail. Thus, appropriate dielectric characteristicscan be selected depending on various purposes. In the case ofsubstituting Ti by Zr, in particular, the absolute value of τ_(f) can belessened while little affecting ε_(r) and Qu. In the case ofsubstituting Ti by Sn, τ_(f) and Qu can be controlled in detail whilelittle affecting ε_(r).

In the case where less than 30% by mol of Al is substituted by at leastone member selected form among Ga, Y and Yb, each of the dielectriccharacteristics can be controlled within the neighborhood of thecorresponding level of the unsubstituted composition. In the case ofsubstituting by Y and Yb, in particular, the absolute value of τ_(f) canbe lessened.

In the case where less than 30% by mol of M² is substituted by Sb, thedegree of sintering can be particularly improved and desired dielectriccharacteristics can be stably obtained.

The electronic component according to the invention can exhibit an ε_(r)of about 45 to 65 and a sufficiently lessened τ_(f) while sustainingwell-balanced ε_(r) and Qu. Thus, it is possible to obtain an electroniccomponent having well-balanced dielectric characteristics in detail. Inparticular, the ε_(r) can be highly selectively determined and,furthermore, an τ_(f) can be obtained while sustaining well-balancedε_(r) and Qu.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 presents charts showing the data obtained by X-ray diffractometryin Experimental Example 1 (lower chart) and Experimental Example 2(upper chart).

FIG. 2 is a model view showing the outline of a dielectric resonatorwhich is an example of the electronic component according to theinvention.

FIG. 3 is a perspective view showing the outline of a duplexer which isan example of the electronic component according to the invention.

FIG. 4 is a sectional model view of the duplexer shown in FIG. 3.

FIG. 5 is a ternary diagram showing the correlationship among s, t and rin the case of represented the dielectric material according to theinvention by the compositional formula [2].

ILLUSTRATION OF NUMERICAL SYMBOLS

1: dielectric resonator, 11: dielectric part, 12: casing, 2: duplexer,21: dielectric part, 211: resonator (through hole), 212: excitation hole(through hole), 22: conductor.

DETAILED DESCRIPTION OF THE INVENTION

Now, the invention will be illustrated in greater detail.

The dielectric material according to the invention is a dielectricmaterial containing Ca, Ti, Al, Nb and O, wherein these elements fulfillthe following requirements when represented by a compositional formula[aM¹O-bTiO₂-(½)cAl₂O₃-(½)dM² ₂O₅] (wherein a, b, c and d represent eacha molar ratio, provided that a+b+c+d=1): 0.436<a≦0.500; 0.124<b≦0.325;0.054<c≦0.150; and 0.170<d<0.346. Hereinafter, this compositionalformula will be referred to as the compositional formula [1].

In the above formula, [M¹] represents at least one of Ca and Sr. In thecase where M¹ is Ca alone, therefore, the compositional formula [1] is[aCaO-bTiO₂-(½)cAl₂O₃-(½)dM² ₂O₅]. In the case where M^(l) is Sr alone,therefore, the compositional formula [1] is [aSrO-bTiO₂-(½)cAl₂O₃-(½)dM²₂O₅]. In the case where M^(l) comprises both of Ca and Sr, therefore,the compositional formula [1] is[a(Ca_(1-x)Sr_(x))O-bTiO₂-(½)cAl₂O₃-(½)dM² ₂O₅], provided that 0<x<1.

That is to say, M¹ may be either “Ca alone”, “both of Ca and Sr” or “Sralone”. Ca and Sr can be substituted at an arbitrary ratio. In the casewhere M¹ comprises both of Ca and Sr, the range of x is not particularlyrestricted. For example, x maybe set as 0.01≦x≦0.5, more specifically0.01≦x≦0.3, still specifically 0.01≦x≦0.1.

In the above formula, “a” represents the molar ratio of M¹O in thecompositional formula [1]. a is set as 0.436<a≦0.500, preferably as0.444<a≦0.500 and still preferably as 0.451<a≦0.500. When a falls withinthis range, a particularly large Qu can be obtained while maintainingε_(r) at an appropriate level.

In the above formula, “b” represents the molar ratio of TiO₂ in thecompositional formula [1]. b is set as 0.124<b≦0.325, preferably as0.124<b≦0.300 and still preferably as 0.133<b≦0.275 and particularlypreferably as 0.141<b≦0.275. When b falls within this range, theabsolute value of τ_(f) can be particularly lessened while maintainingε_(r) at an appropriate level.

A part of Ti may be substituted by Zr and/or Sn. In the case where Ti ispartly substituted by Zr alone, the compositional formula [1] is[aM¹O-b(Ti_(1-α)Zr_(α))O₂-(½)cAl₂O₃-(½)dM² ₂O₅]. In the case where Ti issubstituted by Sn alone, the compositional formula [1] is[aM¹O-b(Ti_(1-β)Sn_(β))O₂-(½)cAl₂O₃-(½)dM² ₂O₅].[aSrO-bTiO₂-(½)cAl₂O₃-(½)dM² ₂O₅]. In the case where Ti is substitutedby both Zr and Sn, the compositional formula [1] is[aM¹O-b(Ti_(1-α-β)Zr_(α)Sn_(β))O₂-(½)cAl₂O₃-(½)dM² ₂O₅].

Although the amount of Ti substituted by Zr and/or Sn is notparticularly restricted, it is preferable that less than 30% by mol(still preferably 0.01 to 10% by mol and particularly preferably 0.01 to5% by mol) of Ti is substituted by referring the total Ti content in thedielectric material as to 100% by mol. That is, 0<α<0.3 is preferable(still preferably 0.01≦α≦0.1 and particularly preferably 0.01≦α≦0.05) inthe case β=0. In the case α=0, 0<β0.3 is preferable (still preferably0.01≦β≦0.1 and particularly preferably 0.01≦β≦0.05). In the case α≠0 andβ≠0, 0<α+β<0.3 is preferable (still preferably 0.01≦α+β≦0.1 andparticularly preferably 0.01≦α+β≦0.05). Within the ranges as specifiedabove, each of the dielectric characteristics can be controlled withinthe neighborhood of the corresponding level of the unsubstitutedcomposition. In the case of substituting Ti by Zr, for example, theabsolute value of τ_(f) can be lessened while little affecting ε_(r) andQu. In the case of substituting Ti by Sn, the absolute value of τ_(f)can be lessened or Qu can be improved while little affecting ε_(r).Thus, dielectric characteristics can be controlled in detail.

In the above formula, “c” represents the molar ratio of Al₂O₃in thecompositional formula [1]. c is set as 0.054<c≦0.150, preferably as0.062<c≦0.150, and still preferably as 0.069<c≦0.150, still preferablyas 0.075<c≦0.150 and particularly preferably as 0.079<c≦0.150. When cfalls within this range, the absolute value of τ_(f) can be regulated toparticularly small while maintaining ε_(r) at an appropriate level.

Al may be partly substituted by at lease one of Ga, Y and Yb. In thecase where Al is substituted by such element(s), the compositionalformula [1] is expressed as in the above-described case of Ti. Althoughthe amount of Al substituted by Ga, Y and Yb is not particularlyrestricted, it is preferable that less than 30% by mol (still preferably0.01 to 10% by mol and particularly preferably 0.01 to 5% by mol) of Alis substituted by referring the total Al content in the dielectricmaterial as to 100% by mol. Within the ranges as specified above, eachof the dielectric characteristics can be controlled within theneighborhood of the corresponding level of the unsubstitutedcomposition. In the case of substituting by Y and Yb, in particular, theabsolute value of τ_(f) can be lessened.

In the above formula, [M²] represents at least one of Nb and Ta. In thecase where M² is Nb alone, therefore, the compositional formula [1] is[aM¹O-bTiO₂-(½)cAl₂O₃-(½)dNb₂O₅]. In the case where M¹ is Ta alone,therefore, the compositional formula [1] is[aM¹O-bTiO₂-(½)cAl₂O₃-(½)dTa₂O₅]. In the case where M² comprises both ofNb and Ta, therefore, the compositional formula [1] is[aM¹O-bTiO₂-(½)cAl₂O₃-(½)d(Nb_(1-y)Ta_(y))₂O₅], provided that 0<y<1.

That is to say, M² may be either “Nb alone”, “both of Nb and Ta” or “Taalone”. Among these cases, however, “Nb alone” or “both of Nb and Ta” ispreferred. In these cases, Qu can be elevated while maintaining ε_(r) atan appropriate level and, furthermore, τ_(f) can be easily controlledwithin an appropriate range. In the case where M² comprises both of Nband Ta, the range of y is not particularly restricted. For example, ymay be set as 0.01≦y≦0.5, more specifically 0.01≦y≦0.3, stillspecifically 0.05≦y≦0.2. When y falls within this range, Qu can beelevated while regulating effects on ε_(r) and the absolute value ofτ_(f) can be lessened.

In the above formula, “d” represents the molar ratio of M² ₂O₅ in thecompositional formula [1]. d is set as 0.170<d<0.346, preferably as0.170<d≦0.323 and still preferably as 0.170<d≦0.300. When d falls withinthis range, a particularly large ε_(r) can be obtained while maintainingQu at an appropriate level.

M² may be partly substituted by at Sb. In the case where M² issubstituted, the compositional formula [1] is expressed as in theabove-described case of Ti. Although the amount of M² substituted is notparticularly restricted, it is preferable that less than 30% by mol(still preferably 0.01 to 20% by mol and particularly preferably 0.01 to10% by mol) of M² is substituted by referring the total M² content inthe dielectric material as to 100% by mol. Within the ranges asspecified above, the degree of sintering can be improved and, as aresult, desired dielectric characteristics can be stably obtained.

The preferable ranges of a to d as specified above may be combined witheach other. For example, the following combinations are available:0.436<a≦0.500, 0.124<b≦0.300, 0.062<c≦0.150 and 0.170<d<0.346;0.436<a≦0.500, 0.124<b≦0.275, 0.069<c≦0.150 and 0.170<d<0.346;0.444<a≦0.500, 0.133<b≦0.275, 0.075<c≦0.150 and 0.170<d≦0.323; and, inparticular, 0.451<a≦0.500, 0.141<b≦0.275, 0.079<c≦0.150 and0.170<d<0.300. Within these ranges, a large Qu can be obtained whilemaintaining ε_(r) at an appropriate level and lessening the absolutevalue of τ_(f). Namely, it is possible to obtain, for example, ε_(r) of45 or more (usually not greater than 65), Quxf_(D) of 10000 GHz or moreand τ_(f) of −15 to +15 ppm/° C.

Although the crystalline phase contained in the dielectric material isnot particularly restricted, it is preferable that the crystalline phaseis a crystalline phase of the perovskite structure having a majorcrystalline phase represented by a compositional formula [M¹(Al_(κ)M²_(κ)Ti_(1-2κ))O₃] (wherein 0.175≦κ≦0.3). It may further have a minorcrystalline phase, though having no minor crystalline phase ispreferred. That is to say, it is preferred that the major crystallinephase has a solid solution of an element which is not involved in theabove compositional formula.

In addition to the composition represented by the compositional formula[1], the dielectric material may further contain a transition metaloxide (including a multiple oxide), an oxide containing at least one ofB, Si, Ga, In, Sn, Sb, Pb and Bi (including a multiple oxide). Theoxidation value (valency) of such an element in the dielectric materialis not particularly restricted. Examples of the transition metal elementas cited above include Mn, V, Cr. Fe, Co, Ni, Cu, Zn, Zr, Mo, Hf and W.Among the transition metal elements and other elements as cited above,transition metal elements are preferred. Among them, Mn, Fe, Co, Ni andCu are still preferred and Mn is particularly preferred. Either one ofthese transition metal elements or two or more thereof may be used. Mnparticularly contributes to improvements in dielectric characteristics.Although the content of the oxide(s) is not particularly restricted, itis preferable that the total content of the oxides of these elements is5% by mol or less (still preferably 2% by mol or less, still preferably1% by mol or less and particularly preferably 0.6% by mol or less andusually 0.01% by mol or more when contained) referring the wholedielectric material as to 100% by mol. Within this range, a large Qu canbe easily maintained. Such an oxide may be contained for any reason. Forexample, it may be derived from an oxide employed as an oxygen donorduring the production.

In calculating in terms of oxides, these elements are referred asrespectively to MnO₂, V₂O₅, Cr₂O₃, Fe₂O₃, CoO, NiO, CuO, ZnO, ZrO₂,MoO₃, HfO₂, WO₃, B₂O₃, SiO₂, Ga₂O₃, In₂O₃, SnO₂, Sb₂O₃, PbO₂ and Bi₂O₃.

In addition to the composition represented by the compositional formula[1], the dielectric material may further contain a rare earth metal (RE)oxide (including a multiple oxide). Owing to the presence of RE, each ofthe dielectric characteristics can be controlled at a greater degree offreedom. The oxidation value (valency) of such an element in thedielectric material is not particularly restricted. Examples of the REas cited above include La, Nd, Sm, Y, Yb, Sc, Ce, Pr, Pm, Eu, Gd, Tb,Dy, Ho, Er, Tm, Yb and Lu. Among them, La, Nd, Sm, Y and Yb arepreferred. Either one of these REs or two or more thereof may be used.Although the content of the oxide(s) is not particularly restricted, itis preferable that the total content of RE (in terms of RE₂O₃) is 10% bymol or less (still preferably 8% by mol or less and still preferably 6%by mol or less and usually 0.1% by mol or more when contained) referringthe whole dielectric material as to 100% by mol. Within this range, alarge Qu and a small absolute value of τ_(f) can be obtained whilemaintaining ε_(r) at an appropriate level.

The dielectric material represented by the compositional formula [1] canbe regarded as a dielectric material which comprises solid solutions ofthree types of multiple oxides, i.e., M¹TiO₃, M¹(Al_(0.5)M² _(0.5))O₃and M¹M² ₂O₆ in each other. That is to say, it can be represented by acompositional formula [rM¹TiO₃-sM¹(Al_(0.5)M² _(0.5))O₃-tM¹ _(1/3)M²_(2/3)O_(6/3)] (wherein M¹ is Ca and/or Sr; M² is Nb and/or Ta; and r, sand t represent each a molar ratio, provided that r+s+t=1) (Hereinafter,this compositional formula will be referred to as the compositionalformula [2].)

In the case where the correlationship among r, s and t in thiscompositional formula [2] is expressed in a ternary diagram, it ispreferable that points corresponding respectively to r, s and t arelocated in the area excluding the side P¹P² in the quadrangle havingapexes P¹P²P³P⁴ in FIG. 5. It is still preferable that r, s and t arelocated in the area excluding the side P^(1′)P² in the quadrangle havingapexes P^(1′)P²P³P^(4′) and particularly preferably in the areaexcluding the side P^(1′)P² in the quadrangle having apexesP^(1′)P²P^(3′)P^(4″), provided that the points (r, s, t) are specifiedas follows.

P¹; (0.4879, 0.2627, 0.2494)

P²; (0.3702, 0.5553, 0.0745)

P³; (0.18, 0.27, 0.55)

P⁴; (0.2925, 0.1575, 0.55)

P^(1′); (0.4466, 0.3654, 0.1880)

P^(3′); (0.22, 0.33, 0.45)

P^(4′); (0.2475, 0.2025, 0.55)

P^(4″); (0.3025, 0.2475, 0.45)

Within these areas, characteristics with a smaller absolute value ofτ_(f) can be obtained. It is seemingly preferable that the compositioncontains M¹M² ₂O₆ (expressed as M¹ _(1/3)M² _(2/3)O_(6/3) in thecompositional formula [2]) among the multiple oxides as described above.This is because the presence of M¹M² ₂O₆ would elevate ε_(r) to adesired level while maintaining other dielectric characteristics such asQu and τ_(f) each at an appropriate level

In the dielectric material according to the invention, ε_(r) can be setas 45 to 63 (more specifically 48 to 60 and still specifically 50 to 58,in particular, 53 to 58). It is also possible to set the product of Quand resonance frequency f₀ (Quxf₀) as 10000 GHz or more (morespecifically 11000 GHz or more, still specifically 12000 GHz or more, inparticular, 12500 GHz or more). It is also possible to set thetemperature factor (τ_(f)) of resonance frequency as −15 to +15 ppm/° C.(more specifically −12 to +12 ppm/° C., further more preferably −10 to+10 ppm/° C., and still further more preferably, −5 to +5 ppm/° C.)

In the case where it is desired to obtain a particularly large ε_(r)while maintaining favorable balance with other dielectriccharacteristics, for example, use may be made of a combination0.444≦a≦0.462, 0.133≦b≦0.173, 0.096≦c≦0.108 and 0.261≦d≦0.323. Thus, itis possible to control ε_(r) to 53 to 59, Quxf₀ to 10000 to 13000 GHzand τ_(f) to 0 to 15 ppm/° C.

In the case where it is desired to obtain a particularly large Qu whilemaintaining favorable balance with other dielectric characteristics, forexample, use may be made of a combination 0.458≦a≦0.487, 0.124≦b≦0.217,0.117≦c≦0.129 and 0.175≦d≦0.292. Thus, it is possible to control ε_(r)to 47 to 53, Quxf₀ to 12500 to 15000 GHz and τ_(f) to −15 to 0 ppm/° C.

In the case where it is desired to obtain a particularly small absolutevalue of τ_(f) while maintaining favorable balance with other dielectriccharacteristics, for example, use may be made of a combination0.432≦a≦0.487, 0.144≦b≦0.223, 0.101≦c≦0.139 and 0.175≦d≦0.323. Thus, itis possible to control ε_(r) to 48 to 58, Quxf₀ to 9000 to 15000 GHz andτ_(f) to −4 to 4 ppm/° C.

That is to say, the dielectric characteristics can be controlled over awide range depending on the purpose to give well-balanced dielectriccharacteristics in greater detail. Namely, dielectric characteristicsappropriate for various purposes can be selected.

[2] Method of Producing Dielectric Material

The dielectric material according to the invention may be produced by anarbitrary method without particular restriction. For example, it can beobtained by heating a starting composition containing M¹, Al, Ti and M²each in such an amount as to give the molar ratios of M¹, Al, Ti and M²as specified in the compositional formula [1].

To obtain a dielectric material containing the above-described elementsavailable as substitutes for M¹, Al, Ti and M², it can be obtained byheating a starting composition containing M¹, Al, Ti, M² and theelements available as the substitute therefor each in such an amount asto give the molar ratios of M¹, Al, Ti, M² and the elements available asthe substitute therefor as specified in the compositional formula [1].

To obtain a dielectric material containing side components such as Mnand RE in addition to the compositional formula [1], it can be obtainedby heating a starting composition containing M¹, Al, Ti and M² each insuch an amount as to give the molar ratios of M¹, Al, Ti and M² and theelements constituting the side components each in such an amount as tofulfill the requirement as specified above.

The starting composition may be a mixture of materials individuallycontaining the elements. Alternatively, it may be a mixture of multipleoxides each containing plural elements.

Examples of the materials individually containing the elements asdescribed above include Ca compounds, Sr compounds, Al compounds, Ticompounds, Nb compounds, Ta compounds, Zr compounds, Sn compounds, Ycompounds, Yb compounds, Sb compounds and other RE compounds.Furthermore, each of these compounds may be in the form of an oxide ofthe corresponding element or a compound which can be converted into anoxide by heating, Such compounds which can be converted into oxides byheating is not particularly restricted in type. For example, carbonates,hydroxides, hydrgencarbonates, nitrates and organic metal compounds maybe cited. Either one of these oxides and compounds which can beconverted into oxides by heating or a mixture of two or more thereof maybe employed. These materials are not particularly restricted in form.Namely, use may be made of, for example, powdery materials, and liquidmaterials. Examples of the multiple oxides containing plural elementsinclude CaTiO₃, SrTiO₃, (Ca_(0.5)Sr_(0.5)) TiO₃,Ca(Al_(0.5)Nb_(0.5))TiO₃, Ca(Al_(0.5)Ta_(0.5))TiO₃,Ca(Al_(1/2)Nb_(1/4)Ta_(1/4))TiO₃, CaNb₂O₆, CaTa₂O₆ andCa(Nb_(0.5)Ta_(0.5))₂O₆. Either one of these multiple oxides or amixture of two or more thereof may be used. Moreover, it may be usedeither with of without the materials as described above.

The “heating” treatment as described above may be carried out underarbitrary conditions without particular restriction, so long as thedielectric material can be obtained thereby. Namely, the heatingtreatment may be carried out in one step (i.e., sintering alone) or twosteps (i.e., calcining and sintering). In the case of the two-stepheating, the procedures may be performed either continuously ordiscontinuously.

The sintering step (the second heating step in the case of the two stepheating) is a step in which a molded article containing a startingcomposition (calcined components in the case of the two step heating) tobe converted into a dielectric material is sintered. Although thesintering temperature in the sintering step is not particularlyrestricted, it may be controlled to, for example, 1100 to 1700° C.(preferably 1300 to 1600° C.). In the case where the sinteringtemperature falls within this range, the molded article can besufficiently sintered and densified. The sintering time may becontrolled to 1 hour or longer (usually not exceeding 100 hours), thoughthe invention is not restricted thereto.

Moreover, the sintering atmosphere is not particularly restricted.Namely, either an oxidative atmosphere or a non-oxidative atmosphere maybe employed. As an example of the oxidative atmosphere, atmospheric airmay be cited. The term “non-oxidative atmosphere” means an atmospherehaving a low oxygen pressure, i.e., an atmosphere in which the oxygenpressure is maintained usually at 10 Pa or lower (preferably 0.1 Pa orlower and usually higher than 0.0001 Pa). Such a non-oxidativeatmosphere may be constituted by any gases without restriction. Examplesof such gases include inert gases such as nitrogen and rare gases suchas argon. The sintering atmosphere may be either a humid atmosphere or anon-humid atmosphere. The term “humid atmosphere” means an atmosphereunder dew point control in which the due point is maintained usually at90° C. or lower (preferably 80° C. or lower and usually 30° C. orhigher). The sintering may be carried out either under or withoutpressurizing.

The calcining step (the first heating step in the case of the two stepheating) is a step in which a starting composition is sintered to give acalcined product. In the case where a starting composition is preparedby mixing and molded and the molded article is directly sintered withoutcalcining, it is impossible in some cases to sufficiently sinter themolded article in the subsequent sintering step. By calcining, incontrast thereto, the starting composition undergoes a reaction to formaimed compounds and, as a result, the sintering temperature in thesubsequent sintering step can be effectively lowered.

Although the calcining temperature in the calcining step is notparticularly restricted, it may be controlled to, for example, 600 to1400° C. (preferably 800 to 1300° C.). In the case where the calciningtemperature falls within this range, the starting components scarcelyremain unreacted or the starting composition would not be sintered togive a calcined product which can be hardly ground. The calcining timein this calcining step may be controlled to 1 hour or longer (usuallynot exceeding 20 hours), though the invention is not restricted thereto.Moreover, the calcining atmosphere is not particularly restricted andvarious atmospheres may be used as in the sintering atmosphere asdescribed above. The calcining atmosphere may be the same as thesintering temperature or different therefrom.

These heating conditions maybe combined in various ways. For example, adielectric material can be obtained by mixing materials containingindividual elements, calcining the obtained mixture in the atmosphericair at 600 to 1400° C. (preferably 800 to 1300° C.) for 1 to 20 hours,then grinding the calcined product, molding and sintering in theatmospheric air at 1100 to 1700° C. (preferably 1300 to 1600° C.) for 1to 100 hours.

In addition to the heating step(s) as described above, the productionmethod according to the invention may further contain other step(s).Examples of the other steps include (1) a granulation step of grindingthe calcined product and granulating the calcined powder thus obtained,and (2) a molding step of molding the granulated powder obtained in theabove step (1) to give a molded article.

The granulation step is a step in which the calcined product obtained bycalcining is ground and, after adding, for example, a binder, a solvent,a plasticizer and a dispersant, the calcined powder is granulated togive granules suitable for molding. The granulation method is notparticularly restricted and use may be made of, for example, the spraydrying method. The molding step is a step in which the granulated powderobtained in the granulation step is molded to give a molded article. Inthis step, the granulated powder is usually blended with, for example, abinder, a solvent, a plasticizer and a dispersant to impart moldabilitythereto. The molding method is not particularly restricted and use maybe made of various methods such as uniaxial pressing and coldisotropic/isostatic pressing (hereinafter referred to simply as CIP)therefor.

[3] Electronic Component

The electronic component according to the invention is characterized byhaving a dielectric part made of the dielectric material.

The “dielectric part” as described above is made of the dielectricmaterial according to the invention and not restricted in shape or size.This dielectric part is usable as a ceramic part of, for example, afilter, a duplexer, a resonator, an LC device, a coupler, a diplexer, adiode, a dielectric antenna, a ceramic condenser, a circuit board and apackage. Namely, it is preferably made into a shape and size appropriatefor the purpose.

The electronic component may have other part(s) in addition to thedielectric part. As an example of the other parts, a conductor part maybe cited. A conductor part usually means a part having electricalconductivity which is formed on the surface and/or inside of thedielectric part. This conductor part may be either sinteredsimultaneously with the dielectric part or separately sintered.Conductor materials constituting the conductor part are not particularlyrestricted. For example, use may be made of Ag, Cu, Au, Ni, Al, W, Ti,V, Cr, Mn, Mo, Pd, Pb, Ru, Rh and Ir therefor. Either one of thesematerials or two or more thereof may be employed.

As an example of the electronic component according to the invention, adielectric resonator having a cylindrical dielectric part made of thedielectric material according to the invention may be cited.

Other examples thereof include a duplexer and a dielectric filter eachprovided with a dielectric part which is in a rectangular shape and hasa plural number of aligned through holes and a conductor part coveringthe definite external face of the dielectric part and the inner part ofthe through holes.

Another example thereof is a layered dielectric chip antenna having aplural number of dielectric parts in the form of thin plates layeredtogether, conductor patterns formed among the dielectric parts and athrough hole conductor or an external face conductor electricallyconnecting the conductor patterns.

Still another example thereof is a dielectric hip antenna having arectangular dielectric part, a power supplying electrode located at oneend in the longitudinal direction of the dielectric part, a fixedelectrode located at the other end and a radiation electrode spirallywound around the side wall of the dielectric part with one end beingconnected to the power supplying electrode while the other end beingfree.

Further examples thereof include an LC filter, a ceramic condenser and aceramic circuit board each having a plural number of dielectric parts inthe form of thin plates layered together, conductor patterns formedamong the dielectric parts and a through hole conductor or an externalface conductor electrically connecting the conductor patterns.

EXAMPLES

Now, the invention will be illustrated in greater detail by referring tothe following examples.

(1) Production of Dielectric Material

Commercially available powders of CaCO₃, SrCO₃, TiO₂, Al₂O₃, Nb_(2l O)₅, Ta₂O₅, MnO₂, RE₂O₃, ZrO₂, SnO₂, Ga₂O₃ and Sb₂O₅ were weighed so as togive each combination of the values a to d, in terms of oxides, in thecompositional formula [1] as specified in Table 1. Then these powders(starting materials) were wet-mixed with the-use of ethanol as a solventto give a powdery mixture (a starting composition). This powdery mixturewas calcined in the atmospheric air at 1200° C. for 2 hours. Next, adispersant, a binder and ethanol were added to this calcined product andthe mixture was ground in a ball mill to give a slurry. Then this slurrywas dried and granulated to give a granular powder. This granular powderwas molded into columns by uniazxially pressing under pressure of 20MPa. Subsequently, the molded article was subjected to CIP (coldisotropic/isostatic press) treatment under pressure of 150 MPa,maintained at 500° C. for 3 hours and then sintered. Thus, dielectricmaterials made of the dielectric materials of Experimental Examples 1 to49 were obtained. TABLE 1 aCaO-bTiO₂-(1/2) cAl₂O₃-(1/2) dNb₂O₅ MnO₂RE₂O₃ Qu × f₀ τ_(f) a b c d (mol %) (mol %) RE ε_(r) (GHz) (ppm/K) 10.4815 0.2222 0.1111 0.1852 0.3884 — — 54 12400 12 *2 0.4286 0.14290.0714 0.3571 0.3485 68 2600 65 3 0.4815 0.2133 0.1156 0.1896 0.3889 5212800 4 4 0.4865 0.2162 0.1216 0.1757 0.3942 50 14200 −2 5 0.4815 0.19440.1250 0.1991 0.3901 49 13400 −10 6 0.4706 0.1765 0.1176 0.2353 0.380152 12900 −4 7 0.4583 0.1250 0.1250 0.2917 0.3718 48 13200 −15 8 0.48650.2027 0.1284 0.1824 0.3951 48 14400 −9 9 0.4706 0.2059 0.1029 0.22060.3784 56 12000 13 10 0.4646 0.1970 0.0985 0.2399 0.3734 58 11500 15 110.4646 0.1818 0.1061 0.2475 0.3743 55 12100 7 12 0.4762 0.2000 0.11430.2095 0.3842 52 13000 3 13 0.4583 0.1563 0.1094 0.2760 0.3701 53 120000 14 0.4516 0.1452 0.1048 0.2984 0.3652 54 11300 0 15 0.4516 0.16130.0968 0.2903 0.3643 58 10800 11 16 0.4444 0.1333 0.1000 0.3222 0.360254 10000 3

In Table 1, “*” means being excluded from the scope of the invention.TABLE 2 aCaO-bTiO₂-(1/2) cAl₂O₃-(1/2) dNb₂O₅ MnO₂ RE₂O₃ Qu × f₀ τ_(f) ab c d (mol %) (mol %) RE ε_(r) (GHz) (ppm/K) 17 0.4583 0.1719 0.10160.2682 0.3693 — — 57 11300 10 18 0.4550 0.1505 0.1073 0.2872 0.3677 5411700 0 19 0.4615 0.1692 0.1077 0.2615 0.3722 54 12000 4 20 0.46770.1791 0.1119 0.2413 0.3772 53 12600 0 21 0.4550 0.1667 0.0992 0.27910.3668 57 11100 11 22 0.4583 0.1641 0.1055 0.2721 0.3697 55 11800 6 230.4550 0.1587 0.1032 0.2831 0.3672 56 11500 6 24 0.4516 0.1532 0.10080.2944 0.3647 56 11000 11 25 0.4789 0.2254 0.1056 0.1901 0.3854 56 1250015 26 0.4571 0.2286 0.1143 0.2000 0.3767 2.8571 La 54 12000 12 27 0.44440.2222 0.1389 0.1944 0.3767 5.5556 La 49 12900 −2 28 0.4583 0.17190.1016 0.2682 0.3693 1.0000 Sn 55 11700 2 29 0.4444 0.2029 0.1304 0.22220.3725 4.3478 La 51 12300 −1 30 0.4571 0.2286 0.1143 0.2000 0.37672.8571 La/Nd 54 12400 8 31 0.4571 0.2286 0,1143 0.2000 0.3767 2.8571La/Sn 54 12400 9

TABLE 3 aCaO-bTiO₂-(1/2) cAl₂O₃-(1/2) dNb₂O₅ Ca substi- Ti substi- Alsubsti- Nb substi- MnO₂ Qu × f₀ τ_(f) a tution (%) b tution (%) c tution(%) d tution (%) (mol %) ε_(r) (GHz) (ppm/K) 17 0.4583 0.1719 0.10160.2682 0.3693 57 11300 10 32 0.4583 2.5(Sr) 0.1719 — 0.1016 — 0.2682 —0.3693 58 11100 10 33 5.0(Sr) 58 10600 13 34 0.4583 — 0.1719 2.5(Zr)0.1016 — 0.2682 — 0.3693 54 11300 2 35 5.0(Zr) 56 11100 8 36 2.5(Sn) 5611700 2 37 5.0(Sn) 53 11900 −2 38 0.4789 — 0.2254 2.5(Sn) 0.1056 —0.1901 — 0.3854 55 12500 14 39 5.0(Sn) 54 12500 9 40 0.4583 — 0.1719 —0.1016 2.5(Y) 0.2682 — 0.3693 55 11600 6 41 5.0(Y) 55 11600 2 42 2.5(Yb)56 11600 6 43 5.0(Yb) 55 10900 3 44 2.5(Ga) 57 11300 10 45 5.0(Ga) 5811100 13 46 0.4583 — 0.1719 — 0.1016 — 0.2682 10(Ta) 0.3693 56 11800 847 20(Ta) 55 12500 6 48 2.5(Sb) 54 10100 5 49 5.0(Sb) 55 10300 7

In Experimental Example 32, for example, “a=0.4583” means the totalmolar ratio of CaO and SrO. That is, the above “CaCO₃” was substitutedby “SrCO₃” so as to give an Sr content of 0.0115 (molar ratio) amountingto “2.5%” of the whole “a”. The same applies to “Ti substitution”, “Alsubstitution” and “Nb substitution”.

(2) Measurement of Dielectric Characteristics

Surface of each of the obtained dielectric materials of ExperimentalExamples 1 to 49 was polished. Then, ε_(r), Qu and τ_(f) were measuredby the parallel conductor board dielectric resonator method at ameasuring frequency of 3 to 5 GHz. τ_(f) was measured within atemperature range of from 25 to 80° C. Qu was evaluated as a productwith resonance frequency F₀ (Quxf₀). Tables 1 to 3 summarize theresults.

As Tables 1 to 3 show, a small Quxf₀ value (2600 GHz) and a largeabsolute value of τ_(f)(65) were observed in Experimental Example 2wherein the lower limit of a was less than 0.436 and d exceeded 0.346.

In Experimental Examples 1 and 3 to 49 wherein a, b, c and d all fellwithin the scopes of the invention, in contrast, Quxf₀ values (10000 to14400 GHz) were 3.8 to 5.5 times as high as that of Experimental Example2, which indicates that excellent Qu values were obtained. Further,τ_(f) values were controlled within a relatively narrow numerical rangeof −15 to +15 ppm/° C. and the absolute values thereof were smaller,i.e., 23% of the τ_(f)in Experimental Example 2. In these ExperimentalExamples, ε_(r) values stably fell within the aimed intermediate rangeof from 48 to 58. Namely, the ε_(r) values could be widely controlledwithin this intermediate range. As these results indicate, well-balanceddielectric characteristics can be achieved in detail in these dielectricmaterials, which indicates that appropriate dielectric characteristicscan be selected depending on various purposes.

In Experimental Examples 26 to 31, rare earth element oxides wereemployed as compositions other than the compositional formula [1]. Itcan be understood that, owing to this constitution, the absolute τ_(f)value could be regulated at a small level (−2 to 12) while maintainingthe ε_(r) values stably within the aimed intermediate range of from 49to 54 and maintaining the Quxf₀ products within a range of 11700 to12900 GHz.

Moreover, Experimental Examples 17, 32 and 33 indicate that Ca could besubstituted by Sr while scarcely affecting any dielectriccharacteristics. Experimental Examples 17 and 34 to 37 indicate that, bysubstituting Ti by Zr and/or Sn, τ_(f) could be elevated while littlechanging ε_(r) and Qu. That is, it was observed that τ_(f) values wereelevated by 20 to 80% (the absolute value approximating to 0)respectively by the substitution of 2.5 to 5.0%. Experimental Examples17 and 40 to 43 indicate that, by substituting Al by Y and/or Yb, τ_(f)could be elevated while little changing ε_(r) and Qu. That is, it wasobserved that τ_(f) values were elevated by 40 to 80% (the absolutevalue approximating to 0) respectively by the substitution of 2.5 to5.0%. Experimental Examples 17, 44 and 45 indicate that, Al could besubstituted by Ga while little affecting any dielectric characteristics.Experimental Examples 17 and 46 to 49 indicate that, by substituting Nbby Ta and Sb, τ_(f) could be elevated while little changing ε_(r) andQU. That is, it was observed that τ_(f) values were elevated by 20 to50% (the absolute value approximating to 0) respectively by thesubstitution of 2.5 to 5.0%.

(3) X-Ray Diffractometry

The dielectric materials obtained by Experimental Example 1 (aninvention product) and Experimental Example 2 (a comparative product) inthe above (1) were analyzed by X-ray diffractometry. FIG. 1 shows themultiple diferactometric patterns of the results. In FIG. 1, the upperchart shows the data of Experimental Example 2 while the lower chartshows the data of Experimental Example 1.

When identified, peaks having solid inverted triangles in each chart arepeaks of the major crystalline phase, indicating the formation of theperovskite structure. Peaks having solid circles in the upper chart meanthe deposited minor crystalline phase which was proved as CaNb₂O₆. Basedon these results, it is considered that in the dielectric material ofExperimental Example 1, a solid solution of excessive componentsoccurred in multiple oxides of the perovskite structure comprisingCa(Al_(κ)Nb_(κ)Ti_(1-2κ))O₃ as the base. On the other hand, Nb wascontained in excess to Al and Ti in the dielectric material ofExperimental Example 2 and thus CaNb₂O₃ was seemingly deposited as aseparate phase. Although the CaNb₂O₆ contributed to the improvement inε_(r), it seems preferable that CaNb₂O₆ is not deposited as a separatephase but occurs as a solid solution.

Although peaks having solid inverted triangles in the lower chart areclosely similar to the peaks of the major crystalline phase shown in theupper chart, broadening in the rising and shift of the peak positionwere observed in some peaks. Although the dielectric material containedmaterials in amounts exceeding the level required for the formation ofthe main crystalline phase alone, no peak other than the majorcrystalline phase was observed. These facts seemingly indicate thatexcessive components were in the state of a solid solution in the majorcrystalline phase in the lower chart.

Production of Resonator

Now, a case using the dielectric material as a dielectric resonator willbe illustrated.

Using a granulated powder produced as in Experimental Example 1 in Table1 as described in the above (1), a cylindrical unsintered molded articlewas produced by uniaxially pressing, The unsintered article thusobtained was sintered by maintaining in the atmospheric air at 1500° C.for 3 hours to give a dielectric part (11 in FIG. 2: dielectric part)composed of two cylinders having different outer diameter, i.e., onehaving an inner diameter of 6.8 nm and outer diameter at the upper part(height: 12 nm) of 26 mm being piled upon another having an outerdiameter at the lower part (height: 13 mm) of 15 mm piled thereon. Next,the obtained dielectric part was fixed on the bottom of a metalliccasing 12 to give a resonator 1.

Production of Duplexer

Now, a case using the dielectric material as a duplexer will beillustrated.

Using a granulated powder produced as in Experimental Example 1 in Table1 as described in the above (1), a rectangular unsintered molded article(the same shape as 21 in FIGS. 3 and 4) having aligned through holes(211 and 212 in FIGS. 3 and 4) was produced by uniaxially pressing. Theunsintered article thus obtained was sintered by maintaining in theatmospheric air at 1500° C. for 3 hours to give a dielectric part (21 inFIGS. 3 and 4). Next, a silver paste for conductor was printed and bakedon the definite outer face (including the surface of the through holes)of the dielectric part to form a conductor 22, thereby giving a duplexer2.

Namely, the duplexer 2 has a rectangular dielectric part 21 havingthrough holes aligned in parallel which serve resonators 211 orexcitation holes 212 and a conductor part 22 covering the definite outerface (including the surface of the through holes) of the dielectric part21 excluding the open end with the opening of the through holes.

The invention is not restricted to the specific embodiment examples asdescribed above but various modifications can be made depending on thepurposes and uses within the scope of the invention. Moreover, thedielectric material according to the invention may contain othercomponent(s) and/or unavoidable contaminant(s) so long as the dielectriccharacteristics of the dielectric material are not substantiallyaffected thereby.

The following Table 4 shows r, s and t values of the dielectricmaterials of Experimental Examples 1 to 49 represented by thecompositional formula [2] as described above. TABLE 4rM¹TiO₃-sM³(Al_(0.5)M² _(0.5))O₃-tM¹ _(1/3)M² _(2/3)O_(8/3) r s t  10.4000 0.4000 0.2000 *2 0.2000 0.2000 0.6000  3 0.3840 0.4160 0.2000  40.4000 0.4500 0.1500  5 0.3500 0.4500 0.2000  6 0.3000 0.4000 0.3000  70.2000 0.4000 0.4000  8 0.3750 0.4750 0.1500  9 0.3500 0.3500 0.3000 100.3250 0.3250 0.3500 11 0.3000 0.3500 0.3500 12 0.3500 0.4000 0.2500 130.2500 0.3500 0.4000 14 0.2250 0.3250 0.4500 15 0.2500 0.3000 0.4500 160.2000 0.3000 0.5000 17 0.2750 0.3250 0.4000 18 0.2370 0.3380 0.4250 190.2750 0.3500 0.3750 20 0.3000 0.3750 0.3250 21 0.2625 0.3125 0.4250 220.2625 0.3375 0.4000 23 0.2500 0.3250 0.4250 24 0.2375 0.3125 0.4500 250.4000 0.3750 0.2250 26 0.4000 0.3000 0.3000 27 28 0.2750 0.3250 0.400029 0.3500 0.3000 0.3500 30 0.4000 0.3000 0.3000 31 32 0.2750 0.32500.4000 33 34 35 36 37 38 0.4000 0.3750 0.2250 39 40 0.2750 0.3250 0.400041 42 43 44 45 46 47 48 49

The dielectric part according to the invention is not restricted in usebut usable in various electronic components to be used in the microwavearea and the milliwave area. Examples of these various electroniccomponents include individual parts such as filters, duplexers,resonators, LC devices, couplers, diplexers, diodes, dielectric antennasand ceramic condensers. Further examples thereof include boards such asmultipurpose boards, functional boards having various functional partsembedded therein (for example, multilayer LTCC devices), packages suchas MPU and SAW, and modules having at least one of these individualparts, boards and packages. These electronic components are usable invarious mobile communication devices using radio waves in the microwavearea and/or the milliwave area, mobile communication base devices,satellite communication devices, satellite communication base devices,satellite broadcast devices, wireless LAN devices and Bluetooth(registered trade name) devices.

This application is based on Japanese Patent application JP 2004-288660,filed Sep. 30, 2004, the entire content of which is hereby incorporatedby reference, the same as if set forth at length.

1. A dielectric material containing at least one of Ca and Sr, Ti, Al,at least one of Nb and Ta, and O, wherein these elements fulfill thefollowing requirements when represented by a compositional formula,aM^(l)O-bTiO₂-(½)cAl₂O₃-(½)dM² ₂O₅ wherein M¹ represents the at leastone of Ca and Sr; M² represents the at least one of Nb and Ta; and a, b,c and d represent each a molar ratio, provided that a+b+c+d=1:0.436<a≦0.500; 0.124<b≦0.325; 0.054<c≦0.150; and 0.170<d<0.346.
 2. Thedielectric material as claimed in claim 1, wherein a, b, c and d fulfillthe following requirements: 0.436<a≦0.500; 0.124<b≦0.300; 0.062<c≦0.150;and 0.170<d<0.346.
 3. The dielectric material as claimed in claim 1,wherein a, b, c and d fulfill the following requirements: 0.436<a≦0.500;0.124<b≦0.275; 0.069<c≦0.150; and 0.170<d<0.346.
 4. The dielectricmaterial as claimed in claim 1, wherein a, b, c and d fulfill thefollowing requirements:. 0.444<a≦0.500; 0.133<b≦0.275; 0.075<c≦0.150;and 0.170<d≦0.323.
 5. The dielectric material as claimed in claim 1,wherein a, b, c and d fulfill the following requirements: 0.451<a≦0.500;0.141<b≦0.275; 0.079<c≦0.150; and 0.170<d≦0.300.
 6. The dielectricmaterial as claimed in claim 1, which contains 0.01 to 5% by mol of Mnin terms of MnO₂ by referring a total molar content of metal elements,in terms of oxides, contained in the dielectric material as to 100% bymol.
 7. The dielectric material as claimed in claim 1, which contains0.01 to 2% by mol of Mn in terms of MnO₂ by referring a total molarcontent of metal elements, in terms of oxides, contained in thedielectric material as to 100% by mol.
 8. The dielectric material asclaimed in claim 1, which contains 0.01 to 1% by mol of Mn in terms ofMnO₂ by referring a total molar content of metal elements, in terms ofoxides, contained in the dielectric material as to 100% by mol.
 9. Thedielectric material as claimed in claim 1, which contains 0.01 to 0.6%by mol of Mn in terms of MnO₂ by referring a total molar content ofmetal elements, in terms of oxides, contained in the dielectric materialas to 100% by mol.
 10. The dielectricmaterial as claimed in claim 1,which contains 0.1 to 10% by mol of a rare earth element RE in terms ofRE₂O₃ a by referring a total molar content of metal elements, in termsof oxides, contained in the dielectric material as to 100% by mol. 11.The dielectricmaterial as claimed in claim 1, which contains 0.1 to 8%by mol of a rare earth element RE in terms of RE₂O₃ by referring a totalmolar content of metal elements, in terms of oxides, contained in thedielectric material as to 100% by mol.
 12. The dielectric material asclaimed in claim 1, which contains 0.1 to 6% by mol of a rare earthelement RE in terms of RE₂O₃ by referring a total molar content of metalelements, in terms of oxides, contained in the dielectric material as to100% by mol.
 13. The dielectric material as claimed in claim 10, whereinthe rare earth element is at least one member selected from the groupconsisting of La, Nd, Sm, Y and Yb.
 14. The dielectric material asclaimed in claim 1, wherein less than 30% by mol of Ti is substituted byat least one of Zr and Sn by referring a total Ti content in thedielectric material as to 100% by mol.
 15. The dielectric material asclaimed in claim 1, wherein less than 30% by mol of Al is substituted byat least one member selected from the group consisting of Ga, Y and Ybby referring a total Al content in the dielectric material as to 100% bymol.
 16. The dielectric material as claimed in claim 1, wherein lessthan 30% by mol of M² is substituted by Sb by referring a total M²content in the dielectric material as to 100% by mol.
 17. An electroniccomponent including a dielectric member made of the dielectric materialas claimed in claim 1.